Coupling device for permitting coupling under trapped pressure

ABSTRACT

This invention relates to a valved quick disconnect coupler in which two coupling halves, each connectable to a respective conduit for fluid, may be connected to each other while either or both conduits are under high-fluid pressure.

United States Patent (151 3,646,964 Stratman 1 Mar. 7, 1972 [54]COUPLING DEVICE FOR PERMITTING 3,431,942 3/1969 Kopaska I 377614.05COUPLING UNDER TRAPPED 3,348,575 10/1967 Simak ..137/6l4.05 PRESSUREFOREIGN PATENTS OR APPLICATIONS [72] 996,408 6/1965 Great Britain..l37/614.04 [73] Assignee: Parker-Hannilln Corporation, Cleveland,

0M0 Primary Examiner-Samuel B. Rothberg [22] Filed: Feb. 28, 1967Assistant Examiner-William A. Wright An J h N. W If [21] Appl. No.:619,239 ram [57] ABSTRACT 7 g 7 9 7 This invention relates to a valvedquick disconnect coupler 111 [58] mm .i i i/s idfiia ri i iio i 614.05-which halves each mnneclable a respective 5 1 I499 conduit for fluid,may be connected to each other while either or both conduits are underhigh-fluid pressure. [56] 28 Claims, 3 Drawing Figures UNITED STATESPATENTS 3,215,161 l1/1 9 65 Goodwin ..136/614.04

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, "5* w, (-12" "liviifdku COUPLING DEVICE FOR PERMITTING COUPLING UNDERTRAPPED PRESSURE Valved quick disconnect coupling devices are used toconnect conduit sections of various types of fluid handling systems, oneexample being the fluid lines in a hydraulic system for operatingagricultural implements. Such couplings commonly have a check valve ineach coupling half which is closed when the parts are disconnected butwhich is opened by the act of connecting the coupling halves to eachother. Quite often it is desirable to make the connection while one orboth of the associated conduit sections are under high-fluid pressure.In such cases this is difficult to do by the simple manual act ofpushing the one coupling member into the other because such manualeffort must open the check valves against the high'fluid pressure. Somepresently known couplers have attempted to solve this problem bybalancing the fluid pressures acting on the check valves but this hasproven unsatisfactory.

The present invention solves the problem of connecting while either orboth conduit sections are under high pressure by permitting the checkvalve or valves that are subject to high pressure to remain closed whilethe connection is being made and providing a biasing means that opensthe check valve on the pump or tractor side of the coupler when the pumppressure is relieved and which permits the check valve on the implementor motor side to be opened by pump pressure when the latter isreapplied, such biasing means also acting to maintain the check valvesin open position after they have been opened. The biasing means iscarried by one of the coupling halves and there is another means torender the biasing means ineffective for opening the check valve in thatcoupling half when the two halves are not interconnected.

The invention further provides a means for releasably interlocking thecoupling halves in coupled relation, including a locking sleeve andball-type detent and also including a cocking member that holds thelocking sleeve in a released position when the coupling halves aredisconnected and that permits automatic movement of the locking sleeveto lock position when the coupling halves are in fully coupled positionto thereby facilitate coupling of the coupling members.

The invention also provides a means to prevent fluid trapped between thecheck valves during coupling movement of the coupling halves fromprecluding completion of such coupling movement.

FIG. 1 is a longitudinal central sectional view through the couplershowing the one-half partially inserted into the other.

FIG. 2 is a similar view showing the coupling halves completely coupledand showing the check valves held in closed position by high-fluidpressure.

FIG. 3 is a similar view but showing the check valves in open position.

Coupler includes a socket or female body half 11 that may be connectedby thread 19 to a fluid conduit (not shown) leading from a pump and alsoincludes a tip or male half 12 that is connectable by thread 40 to afluid conduit (not shown) leading to a fluid motor on a farm implementor other device.

Socket 11 includes a shell 15 threaded to a screw tip is hav ing acylindrical extension that has a bore 13 and a valve seat 2] againstwhich a ball check valve 22 may seat.

A shielding sleeve 31 within bore 13 has an enlarged portion 33 thatclosely fits over ball 22 and is integral as by brazing or unitaryconstruction with a spider head 16 whose threaded legs are engaged withthread 19 and with the spaces between the legs providing flow passages17. Spider head 16 has an opening 34 that slidably receives the reducedend 35 of plunger 36 having shoulder 32 that engages spider head 16 tolimit rearward movement of ball 22. Spring 37 urges ball 22 towardclosed position against seat 21.

The check valve arrangement in tip 12 is identical to that in socket 1].Thus tip [2 has a bore 14 ending at a valve seat 38 and it also has ashielding sleeve 41 with an enlargement 43 containing ball check valve39 and with an integral spider head 42 threaded into thread 40 and withflow passages between the spider legs. Spider head 42 has a bore 44 toslidably receive the reduced end of plunger 46 and the latter has ashoulder 45 engageable with spider head 42 to limit opening travel ofball 39 away from seat 38. Spring 47 urges ball check valve 39 towardseat 38.

Shell 15 has an O-ring 80 engageable by tip 12 when the latter isinserted into socket ll. Tip 12 has an annular groove 48 that registerswith an annularly disposed series of detent balls 50 carried in radialholes 49 of shell 15 when tip I2 is fully inserted within socket ll. Acollar 5] is slidably mounted on shell 15 and has a groove 53 to receivedetent balls 50 and another groove 71 to receive another series ofdetent balls 73 carried in radial openings 72 when the collar is in theretracted position shown in FIG. 1. A spring 52 urges the collar towardthe extended position shown in H0. 2 and a snap ring 50a limitsrightward movement of the collar. A cocking sleeve 24 within shell [5has a cylindrical portion 26 which when in register with balls 73maintains the same within groove 71 to prevent rightward movement orextension of collar 51. Sleeve 24 also has a reduced cylindrical portion25 which when in register with balls 73 permit them to retract fromgroove 71 to release collar 50 so that spring 52 will move it toextended position with a snap action. A spring 30 urges cocking sleeve24 to the right as viewed in the drawing and O-rings 29 and 79 makesealing engagement with the cocking sleeve and shell 15.

Mounted within shell 15 is a spider head 23 whose legs are clampedagainst a shoulder 74 within the shell by the forward end ofscrew tip18. Spider head 23 has a central bore 55a into which an end ofa tubularsleeve 55 is pressed. Slidable within sleeve 55 is a cartridge or cage54 that includes an outer sleeve 56 threaded to an inner sleeve 57 andproviding inturned shoulders 58 and S9 at opposite ends thereof.

A spring 6] bears against a shoulder on inner sleeve 57 urging it towardthe right.

Within cage 54 and having portions extending therefrom are plungers 62and 66 respectively having annular shoulders 63, 67 with a spring 70extending therebetween. Plunger 62 has a central bore 65 intersecting across drill 65a. Plunger 66 has a through bore 69.

Shell 15 also contains a metallic volume relief piston 77 slidablymounted on cylindrical extension 20 and sealed with respect thereto by apacking and sealed relative to shell 15 by packing 76. Spring 78 urgespiston 77 toward contact with the legs of spider head 23 and the spacebehind piston 77 is relieved to atmosphere by a bleed port 85.

The coupling parts, when tip 12 is disconnected from socket ll, are inthe positions shown in FIG. 1 regardless of whether there is high-fluidpressure within the tip or socket behind check valves 39 and 22 becausethe check valves are held closed by their respective springs 47 and 37if there is no fluid pressure behind the check valves and by the springsplus fluid pressure if the latter is present. Fluid within shell 15 tothe right of check valve 22 normally will have drained to the exteriorvia bores 65 and 65a during the time that tip 12 is disconnected fromsocket ll.

Assuming that there is high-fluid pressure behind each check valve, astip [2 is brought toward connecting position, ball 39 engages plunger 62as shown in FIG. 1. Further inward movement of the tip will then causespring 61, which has less resistance than either of springs 37, 47 and70, to compress. This permits the cage 54 to be moved to the left byball 39 until plunger 66 engages check valve 22. At this time packing 80will have engaged tip l2 to seal the interior ofthe coupling from theexterior.

Upon further coupling movement of tip l2 to the position shown in FIG.2, spring 70 is compressed and plunger 62 has moved leftward towardplunger 66. Also, tip [2 has engaged cocking sleeve 24 and moved itleftward until reduced cylindrical portion 25 has registered with balls73 permitting them to withdraw from groove 7l. At this time balls 50 arealso in register with groove 48 and spring 52 snaps collar 51 to theright to lock balls 50 into groove 48 and thus securely attach tip 12 tosocket ll.

Check valves 22 and 39 are not under considerable force from spring 70tending to open the same and would open if there was no fluid pressureholding them closed because spring 70 is stronger than either of springs37, 47 but with pressure in the hydraulic lines they remain closed.

During the coupling movement of tip 12, if insufficient fluid hadpreviously drained from the socket through ports 65, 65a, and if bothcheck valves remain closed because of fluid pressure therebehind, thefluid trapped between the check valves, after tip 12 has contactedpacking 80, tends to be compressed as tip 12 is inserted beyond packing80. Because hydraulic fluid is relatively incompressible a pressurewould then be developed on the fluid between check valves 22, 39 by suchfurther movement of tip 12 sufficient to cause piston 77 to move to theleft and thus provide space to the right of the piston for acceptingfluid displaced by tip 12.

Upon completion of the coupling movement, fluid pressure in screw tip 18behind ball check valve 22 may be momentarily relieved by appropriatemanipulation of the hydraulic system directional control valve (notshown) to drop the pressure in the hydraulic line to which screw tip 18is connected. This permits spring 70 to overcome spring 37 and ball 22opens. The directional control valve is again manipulated torepressurize the hydraulic line to which screw tip [8 is connected.Because ball 22 is now open, repressurizing the line connected to screwtip 18 puts pressure fluid into shell 15 between balls 22 and 39 thatopens ball 39 against pressure trapped therebehind. Spring 70 thencauses plungers 62 and 66 to follow balls 39 and 22 respectively totheir open positions and hold them there, as shown in FIG. 3, until thecoupling halves are subsequently disconnected. Stop plungers 35, 46limit the opening movement of balls 22, 39 so that neither ball can moveso far away from its seat that the other ball could shift cartridge 54and reseat.

To disconnect, collar 5! is manually retracted against spring 52 untilgroove 53 registers with balls 50 to release them from groove 48. Tip 12will then be moved toward the right by spring and fluid forces withinthe coupling and as it does so spring 61 will cause cartridge 54 tofollow it rightwardly so as to permit springs 37, 47 to close checkvalves 22, 39 against their respective seats. Spring 30 will also movecocking sleeve 24 to the right to push balls 73 into groove 71 to lockcollar 5] in its retracted position. Rightward movement of the cockingsleeve is limited by engagement of its shoulder 260 with a shoulder inshell and rightward movement of cartridge 54 is limited by itsengagement with shoulder 27 of the cocking sleeve. Spring 78 thenreturns piston 77 to the right.

Sleeves 3] and 41 shield the respective balls 22 and 39 from the effectsof fluid flow to prevent their inadvertent closing. The balls have aclose sliding fit with the inner wall of shielding sleeves 3!, 4] andthe forward portions of the balls that project from the sleeves when theballs are against their seats 2], 38 have no rearwardly facing surfacesacted upon by flowing fluid and the shielding sleeves prevent flowingfluid from impinging on the rear surfaces of the balls within thesleeves. Thus, with the valves open as shown in FIG. 3, if pressurefluid is flowing from screw tip l8 through the coupling and out throughtip 12, sleeve 3| shields ball 22 whereby the flowing fluid exerts onlyfriction force to such ball tending to compress spring 70 and close theball against its seat 21. Likewise, if fluid is returning from tip 12toward screw tip 18, sleeve 41 shields ball 39 to prevent the flowingfluid from exerting a force on ball 39 other than from friction forcarrying ball 39 to its closed position against the opening force ofspring 70.

lclaim:

l. A quick coupling device comprising a pair of coupling members, eachmember having a (spring seated) check valve therein seated by ayieldable means, means for coupling the members to each other, andbiasing means (within the device exerting a force on each of said checkvalves tending to open the same) which when the members are coupledurges both valves toward open position but is yieldable to permit bothvalves to be closed.

2. The coupling device of claim 1 in which the opening force exerted bythe biasing means upon each check valve when the members are coupled isgreater than the force ex erted by the respective check valve (springs)yieldable means whereby each check valve is unseated by the biasingmeans in the event such check valve is subject only to the force of its(spring) yieldable means for seating the same.

3. The coupling device of claim I in which the biasing means is carriedby one of the members and there is a resilient means that moves thebiasing means to an inoperative position relative to the check valve insaid one member when the mem bers are uncoupled whereby the biasingmeans is prevented from exerting an opening force on the check valve insaid one member sufficient to overcome the (spring force) yieldablemeans tending to seat the valve in said one member.

4. The coupling device of claim 1 in which said biasing means comprisesa spring, and means for exerting a preload upon the spring when themembers are uncoupled.

S. The coupling device of claim 1 in which the biasing means includes aspring, said members are coupled by moving the members axially towardeach other, said check valves en gage said biasing means prior to fullcoupling movement of the members, and one of said check valves beingmoveable with its associated member toward the other check valve uponfurther coupling movement of the members when there is a predeterminedfluid pressure in the member containing said one check valve to therebycompress said spring.

6. The coupling device ofclaim 1 in which one ofsaid mem' bers carries atubular sleeve that supports said biasing means.

7. The coupling device of claim 1 in which said biasing means includes acompression spring and a plunger between each check valve and thecompression spring.

8. The coupling device of claim 1 in which there is a stop means foreach check valve to limit the opening movement of the same whereby thebiasing means continues to exert a force on each check valve when bothare fully open that is greater than the closing force exerted on eachcheck valve by its (spring) yieldable means.

9. The coupling device of claim 6 in which one of the members has achamber containing the biasing means, and passage means venting saidchamber to atmosphere when the members are uncoupled.

10. The coupling of claim 1 in which said biasing means includes a pairof spring pressed plungers each engaging a respective one of the checkvalves, a cage supported by one of the members and slidably supportingthe plungers therein, said cage having a shoulder at each end engageablewith a shoulder on a respective one of the plungers for retaining thesame within the cage.

11. The coupling device of claim I in which one of the members has avalve seat and contains a shielding sleeve that has an open end facingsaid seat, said shielding sleeve is closed at its other end, theassociate check valve in said one member projects into said shieldingsleeve at said open end and has a close sliding fit with the inner wallof said shielding sleeve, the shielding sleeve is radially spaced from asurrounding wall of said one member to form a flow passage therebetween,a spring within the shielding sleeve urges the associated check valvetoward said seat, a portion of said check valve is exposed to fluidflowing through said passage when said associated check valve is in openposition, said portion is devoid of a transverse surface facing awayfrom the valve seat whereby fluid flowing past said portion toward saidseat imposes only friction force against said associated check valvetending to close the same, and said biasing means imposes an openingforce against said associated check valve that is greater than the sumof said friction and spring forces to thereby maintain said associatedcheck valve in open position when fluid is flowing through said passagetoward said seat.

l2v The coupling of claim 10 in which the cage is slidably supported bysaid one member and is spring pressed in a direction away from the checkvalve in said one member when the members are uncoupled to carry saidbiasing means to an inoperative position relative to the check valve insaid one member.

13. A coupling device comprising a socket member and a tip member, thetip member being telescopingly received within the socket member to afully coupled position relative thereto, means for interlocking saidmembers when the tip is in said fully coupled position, each of saidmembers having a spring seated check valve therein, one of said membershaving a hollow extension that forms a chamber between said check valveswhen the members are fully coupled, means establishing a seal betweensaid members upon initial movement of the tip member into the socketmember to thereby close said chamber, yieldable means contained withinthe chamber exerting an opening force upon each check valve when themembers are fully coupled, such force being insufficient to open saidcheck valves when the check valves are subject to a closing forceexerted thereupon by a predetermined pressure of fluid trapped withinthe respective members behind the check valves but which opening forceis sufficient to open each check valve against the action of its springwhen the pressure of fluid within the respective member is less thansaid predetermined pressure.

14. The coupling device of claim 13 in which said chamber includes awall moveable in a direction for enlarging said chamber to therebycompensate for decrease of the chamber size as the tip member moves intothe socket member.

15. The coupling of claim 14 in which the movable wall is spring pressedtoward a position for decreasing the chamber Size.

16. A coupling device comprising a socket member and a tip member eachhaving a spring seated check valve therein, means for coupling themembers to each other, biasing means exerting a force on one of saidcheck valves tending to open the same when the members are coupled, suchforce being greater than the seating force exerted upon such check valveby its seating spring, said coupling means including a shoulder on thetip member, first detent means carried by the socket member, a lockingsleeve carried by the socket members and having means in an extendedposition of the locking sleeve to lock the first detent means intoengagement with said shoulder, a spring urging the locking sleeve towardsaid extended position, second detent means carried by the socket memberand movable to a position for engaging an abutment on the locking sleeveto hold the same in a retracted position, a cocking sleeve within thesocket member and spring pressed to a first position in which it holdssaid second detent means in engagement with said abutment, said cockingsleeve being engageable by said tip member and movable by the same to asecond position in which it releases said second detent means, means toretain the cocking sleeve within the socket when the tip member iswithdrawn, and said cocking sleeve having a shoulder engageable withsaid biasing means to retain the latter within said socket member whenthe members are uncoupled.

17. The coupling device of claim 16 in which the second detent means isradially movable into and out of engagement with said abutment means,and the cocking sleeve has first and second cylindrical portions ofdifferent diameters for alternately engaging the second detent meanswhen in register therewith to thereby cause said radial movement.

[8. A coupling device comprising a socket member and a tip member, afirst detent means carried by the socket member, a locking sleeveslidable on the socket member between extended and retracted position, afirst spring urging the locking sleeve towards said extended position,means on the locking sleeve for locking the first detent means inengagement with a shoulder on the tip member for holding the members incoupled position, a second detent means engageable with an abutment onthe locking sleeve to hold the latter in its retracted position, acocking sleeve carried by the socket member and movable by a secondspring to a first position in which it holds the second detent againstsaid abutment, said cocking sleeve being engageable by the tip memberand movable thereby to a second position in which it releases saidsecond detent from engagement with said abutment to thereupon permitsaid first spring to move the locking sleeve to said extended position,a check valve in each member, and a biasing means within the cockingsleeve acting on both check valves tending to open the same when themembers are coupled.

19. The coupling device of claim 18 in which said second detent means isalso carried by the socket member and is a fixed axial distance from thefirst detent means.

20. The coupling device of claim 18 in which the second detent means isradially movable relative to the socket member and said cocking sleevehas a first portion of a diameter which when in register with the seconddetent means permits the latter to move radially inward to a positionout of engagement with said abutment means, and said cocking sleeve hasa second portion of a diameter which when in register with the seconddetent means moves the latter radially outward for engagement with saidabutment.

21. The coupling device of claim 18 in which there is a packing on eachside of the second detent means sealing the cocking sleeve relative tothe socket member.

22. A coupling for releasably connecting and intercommunicating a pairof conduits, including:

a pair of body members, one of which is connected to a conduit leadingto means for supplying fluid under pressure and the other of which isconnected to a conduit leading to a device to be powered by thepressurized fluid,

means for releasably connecting said body members end to end in atelescoping relationship,

said body members having longitudinal bores with opposed annular valveseats located in said bores and disposed in coaxially spacedrelationship when said body members are connected,

check valves in said body members each adapted to seat in fluidtightrelationship against its respective valve seat, resilient meanspositioned within said body members and urging said check valves againsttheir respective seats, and

means located in one of said body members and adapted upon connecting ofsaid body members to exert an un seating force against each of saidcheck valves which force is greater than the seating force exertedagainst each of said check valves by its resilient means but less thanthe sum of seating forces exerted against each of said check valves byits resilient means and by the pressurized fluid in its conduit.

23. The structure of claim 22 further characterized in that saidunseating force exerting means includes spring means which is compressedand moved towards the valve seat of said fluid pressure supplyingconduit body upon connecting of said body members.

24v The structure of claim 22 further characterized in that saidunseating force exerting means includes a pair of spring means alignedend to end, one of which is compressed and moved towards the valve seatof said fluid pressure supplying conduit body member upon connecting ofsaid body members and the other of which remains stationary upon saidconnecting of said body members but is compressed by the check valve ofsaid other body member.

25. The structure of claim 23 further characterized in that saidunseating force exerting means is located in said fluid pressuresupplying conduit body member and is adapted to be engaged by a contactmeans supported on the other body member and to be moved towards saidvalve seat of said pres sure supplying conduit member to increase thecompression of said spring means.

26. The structure of claim 22 further characterized in that saidunseating force exerting means includes a first tube fixed in positionin the bore of one of said body members and containing a spring meansadapted to be compressed upon connecting of said body members and asecond tube in said bore telescoped with respect to said first tube andadapted to be LII said body members.

28. The structure of claim 27 further characterized in that sealingmeans are formed on said second tube and in the bore of the body memberin which said second tube is positioned with said sealing means adaptedto prevent fluid flow through said bore when said body members areunconnected and to permit fluid flow through said bore when said secondtube is moved towards said check valve.

i i I U 8 CERTIFICATE OF CORRJIC'llOIJ Patent No. 36h6 D t d March 7,1972 Inventor(s) Paul E. Stratman It is certified that error appears inthe above-identified patent and that said Letters Patent are herebycorrected as shown below:

In the claims column 3, line 69 delete "(spring sealed)" lines 71-73,delete "(within the device exerting a force on each of said check valvestending to open the same)" Column t line L, delete "(springs)"; line T,delete "(spring) line 1 4 delete "(spring force)"; line 39 delete"(spring)"; line 55 change "associate" to -associ ated--.

Signed and sealed this 25th day of July 1972.

(SEAL) Attest:

ROBERT GOTPSCHALK EDWARD M.FLETCHER, JR.

Commissioner of Patents Attesting Officer

1. A quick coupling device comprising a pair of coupling members, eachmember having a (spring seated) check valve therein seated by ayieldable means, means for coupling the members to each other, andbiasing means (within the device exerting a force on each of said checkvalves tending to open the same) which when the members are coupledurges both valves toward open position but is yieldable to permit bothvalves to be closed.
 2. The coupling device of claim 1 in which theopening force exerted by the biasing means upon each check valve whenthe members are coupled is greater than the force exerted by therespective check valve (springs) yieldable means whereby each checkvalve is unseated by the biasing means in the event such check valve issubject only to the force of its (spring) yieldable means for seatingthe same.
 3. The coupling device of claim 1 in which the biasing meansis carried by one of the members and there is a resilient means thatmoves the biasing means to an inoperative position relative to the checkvalve in said one member when the members are uncoupled whereby thebiasing means is prevented from exerting an opening force on the checkvalve in said one member sufficient to overcome the (spring force)yieldable means tending to seat the valve in said one member.
 4. Thecoupling device of claim 1 in which said biasing means comprises aspring, and means for exerting a preload upon the spring when themembers are uncoupled.
 5. The coupling device of claim 1 in which thebiasing means includes a spring, said members are coupled by moving themembers axially toward each other, said check valves engage said biasingmeans prior to full coupling movement of the members, and one of saidcheck valves being moveable with its associated member toward the othercheck valve upon further coupling movement of the members when there isa predetermined fluid pressure in the member containing said one checkvalve to thereby compress said spring.
 6. The coupling device of claim 1in which one of said members carries a tubular sleeve that supports saidbiasing means.
 7. The coupling device of claim 1 in which said biasingmeans includes a compression spring and a plunger between each checkvalve and the compression spring.
 8. The coupling device of claim 1 inwhich there is a stop means for each check valve to limit the openingmovement of the same whereby the biasing means continues to exert aforce on each check valve when both are fully open that is greater thanthe closing force exerted on each check valve by its (spring) yieldablemeans.
 9. The coupling device of claim 6 in which one of the members hasa chamber containing the biasing means, and passage means venting saidchamber to atmosphere when the members are uncoupled.
 10. The couplingof claim 1 in which said biasing means includes a pair of spring pressedplungers each engaging a respective one of the check valves, a cagesupported by one of the members and slidably supporting the plungerstherein, said cage having a shoulder at each end engageable with ashoulder on a respective one of the plungers for retaining the samewithin the cage.
 11. The coupling device of claim 1 in which one of themembers has a valve seat and contains a shielding sleeve that has anopen end facing said seat, said shielding sleeve is closed at its otherend, the associate check valve in said one member projects into saidshielding sleeve at said open end and has a close sliding fit with theinner wall of said shielding sleeve, the shielding sleeve is radiallyspaced from a surrounding wall of said one member to form a flow passagetherebetween, a spring within the shielding sleeve urges the associatedcheck valve toward said seat, a portion of said check valve is exposedto fluid flowing through said passage when said associated check valveis in open position, said portion is devoid of a transverse surfacefacing away from the valve seat whereby fluid flowing past said portiontoward said seat imposes only friction force against said associatedcheck valve tending to close the same, and said biasing means imposes anopening force against said associated check valve that is greater thanthe sum of said friction and spring forces to thereby maintain saidassociated check valve in open position when fluid is flowing throughsaid passage toward said seat.
 12. The coupling of claim 10 in which thecage is slidably supported by said one member and is spring pressed in adirection away from the check valve in said one member when the membersare uncoupled to carry said biasing means to an inoperative positionrelative to the check valve in said one member.
 13. A coupling devicecomprising a socket member and a tip member, the tip member beingtelescopingly received within the socket member to a fully coupledposition relative thereto, means for interlocking said members when thetip is in said fully coupled position, each of said members having aspring seated check valve therein, one of said members having a hollowextension that forms a chamber between said check valves when themembers are fully coupled, means establishing a seal between saidmembers upon initial movement of the tip member into the socket memberto thereby close said chamber, yieldable means contained within thechamber exerting an opening force upon each check valve when the membersare fully coupled, such force being insufficient to open said checkvalves when the check valves are subject to a closing force exertedthereupon by a predetermined pressure of fluid trapped within therespective members behind the check valves but which opening force issufficient to open each check valve against the action of its springwhen the pressure of fluid within the respective member is less thansaid predetermined pressure.
 14. The coupling device of claim 13 inwhich said chamber includes a wall moveable in a direction for enlargingsaid chamber to thereby compensate for decrease of the chamber size asthe tip member moves into the socket member.
 15. The coupling of claim14 in which the movable wall is spring pressed toward a position fordecreasing the chamber size.
 16. A coupling device comprising a socketmember and a tip member each having a spring seated check valve therein,means for coupling the members to each other, biasing means exerting aforce on one of said check valves tending to open the same when themembers are coupled, such force being greater than the seating forceexerted upon such check valve by its seating spring, said coupling meansincluding a shoulder on the tip member, first detent means carried bythe socket member, a locking sleeve carried by the socket members andhaving means in an extended position of the locking sleeve to lock thefirst detent means into engagement with said shoulder, a spring urgingthe locking sleeve toward said extended position, second detent meanscarried by the sockEt member and movable to a position for engaging anabutment on the locking sleeve to hold the same in a retracted position,a cocking sleeve within the socket member and spring pressed to a firstposition in which it holds said second detent means in engagement withsaid abutment, said cocking sleeve being engageable by said tip memberand movable by the same to a second position in which it releases saidsecond detent means, means to retain the cocking sleeve within thesocket when the tip member is withdrawn, and said cocking sleeve havinga shoulder engageable with said biasing means to retain the latterwithin said socket member when the members are uncoupled.
 17. Thecoupling device of claim 16 in which the second detent means is radiallymovable into and out of engagement with said abutment means, and thecocking sleeve has first and second cylindrical portions of differentdiameters for alternately engaging the second detent means when inregister therewith to thereby cause said radial movement.
 18. A couplingdevice comprising a socket member and a tip member, a first detent meanscarried by the socket member, a locking sleeve slidable on the socketmember between extended and retracted position, a first spring urgingthe locking sleeve towards said extended position, means on the lockingsleeve for locking the first detent means in engagement with a shoulderon the tip member for holding the members in coupled position, a seconddetent means engageable with an abutment on the locking sleeve to holdthe latter in its retracted position, a cocking sleeve carried by thesocket member and movable by a second spring to a first position inwhich it holds the second detent against said abutment, said cockingsleeve being engageable by the tip member and movable thereby to asecond position in which it releases said second detent from engagementwith said abutment to thereupon permit said first spring to move thelocking sleeve to said extended position, a check valve in each member,and a biasing means within the cocking sleeve acting on both checkvalves tending to open the same when the members are coupled.
 19. Thecoupling device of claim 18 in which said second detent means is alsocarried by the socket member and is a fixed axial distance from thefirst detent means.
 20. The coupling device of claim 18 in which thesecond detent means is radially movable relative to the socket memberand said cocking sleeve has a first portion of a diameter which when inregister with the second detent means permits the latter to moveradially inward to a position out of engagement with said abutmentmeans, and said cocking sleeve has a second portion of a diameter whichwhen in register with the second detent means moves the latter radiallyoutward for engagement with said abutment.
 21. The coupling device ofclaim 18 in which there is a packing on each side of the second detentmeans sealing the cocking sleeve relative to the socket member.
 22. Acoupling for releasably connecting and intercommunicating a pair ofconduits, including: a pair of body members, one of which is connectedto a conduit leading to means for supplying fluid under pressure and theother of which is connected to a conduit leading to a device to bepowered by the pressurized fluid, means for releasably connecting saidbody members end to end in a telescoping relationship, said body membershaving longitudinal bores with opposed annular valve seats located insaid bores and disposed in coaxially spaced relationship when said bodymembers are connected, check valves in said body members each adapted toseat in fluidtight relationship against its respective valve seat,resilient means positioned within said body members and urging saidcheck valves against their respective seats, and means located in one ofsaid body members and adapted upon connecting of said body members toexert an unseating force against each of said check valves which forceis greater Than the seating force exerted against each of said checkvalves by its resilient means but less than the sum of seating forcesexerted against each of said check valves by its resilient means and bythe pressurized fluid in its conduit.
 23. The structure of claim 22further characterized in that said unseating force exerting meansincludes spring means which is compressed and moved towards the valveseat of said fluid pressure supplying conduit body upon connecting ofsaid body members.
 24. The structure of claim 22 further characterizedin that said unseating force exerting means includes a pair of springmeans aligned end to end, one of which is compressed and moved towardsthe valve seat of said fluid pressure supplying conduit body member uponconnecting of said body members and the other of which remainsstationary upon said connecting of said body members but is compressedby the check valve of said other body member.
 25. The structure of claim23 further characterized in that said unseating force exerting means islocated in said fluid pressure supplying conduit body member and isadapted to be engaged by a contact means supported on the other bodymember and to be moved towards said valve seat of said pressuresupplying conduit member to increase the compression of said springmeans.
 26. The structure of claim 22 further characterized in that saidunseating force exerting means includes a first tube fixed in positionin the bore of one of said body members and containing a spring meansadapted to be compressed upon connecting of said body members and asecond tube in said bore telescoped with respect to said first tube andadapted to be moved towards the check valve of the fluid pressuresupplying conduit body member upon connecting of said body members witha spring means in said second tube adapted to be compressed uponconnecting of said body members.
 27. The structure of claim 26 furthercharacterized in that said second tube includes means adapted to becontacted by a contact means supported on said other body member and tomove said second tube towards the check valve of the fluid pressuresupplying conduit body member upon connecting of said body members. 28.The structure of claim 27 further characterized in that sealing meansare formed on said second tube and in the bore of the body member inwhich said second tube is positioned with said sealing means adapted toprevent fluid flow through said bore when said body members areunconnected and to permit fluid flow through said bore when said secondtube is moved towards said check valve.